Workpiece regulating drive units for grinding machines



Oct. 24, 19 67 H. w. WHITE 3,348,343

WORKPIECE REGULATING DRIVE UNITS FOR GRINDING MACHINES Filed May 10, 1965 3 Sheet-Sheet 1 INVENTOR HAROLD W. WHITE ATTYS H. w. WHITE 3,

WORKPIECE REGULATING DRIVE UNITS FOR GRINDING MACHINES Oct. 24, 1967 Filed May 10, 1965 3 Sheets-Sheet 2 INVENTOR.

HAROLD W. WHITE H. W. WHITE Oct. 24, 1967 3 Sheets-Sheet 5 Filed May 10, 1965 INVENTOR. HAROL 0 W. WH/TE ATTYS.

United States Patent 3,348,343 WORKPIECE REGULATING DRIVE UNITS FOR GRINDING MACHINES Harold W. White, Wilson, N.Y., assignor to Cocker Saw Company, Inc., Burt, N.Y., a corporation of New York Filed May 10, 1965, Ser. No. 454,599 3 Claims. (Cl. 51237) ABSTRACT OF THE DISCLOSURE A regulating drive unit for rotating a substantially flat surfaced workpiece during abrading operations having rotatable drive elements driven at different speeds relative to their distance from the axis of rotation of said workpiece.

The present invention relates to improvements in work piece drive units useful with grinding machines for performing various abrading operations, such as grinding, polishing, bufling or brushing, on flat or radial surfaces of disc and ring-shaped workpieces.

Most presently known grinding machines are adapted to grind workpieces having either cylindrical or fiat surfaces, but not both. If it is necessary to grind both types of workpieces two machines must be employed. Since these machines are relatively large and expensive, this creates an obvious disadvantage, and especially if the work load is such that one or both machines are idle during a substantial part of the working day.

Accordingly, it is one of the objects of the present invention to provide a workpiece regulating drive unit which may be used in a conventional grinding machine for cylindrical workpieces to adapt it to grind flat surfaces as well.

The reciprocating and rotary type flat surface grinding machines presently known employ some sort of device for holding the work, such as magnetic, vacuum or mechanical chuck. These devices often distort or otherwise damage the work and are, therefore, not always entirely satisfactory.

It is another object of this invention to provide a regulating drive unit for use with grinding machines which obviates the need for work holding devices that might damage the work.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of a workpiece regulating drive unit for a grinding machine constructed in accordance with the teachings of the present invention.

FIGURE 2 is a plan view of the unit.

FIGURE 3 is a side elevation view of the unit, partly in section.

FIGURE 4 is a front elevation view, partly broken away, of the unit of FIGURES 1-3.

FIGURE 5 is a front elevation View, partly broken away, of a modified form of the unit.

Referring to the drawings, a workpiece regulating drive unit of the present invention includes a housing 11 mounted on a base 12 and having a top surface 14. The base 12 may be provided with suitable holes 16 for bolting the unit to the floor.

As best shown in FIGURE 3, the housing 10 includes upstanding walls 18, 18, 18 provided with aligned holes carrying bearings 20 for rotatably supporting a drive shaft 22. The walls are also provided with additional aligned holes and bearings 24 for rotatably supporting a driven shaft 26 and stationary shaft 28 substantially parallel to and disposed between the drive shaft 22 and the top surface 14. The top surface is provided with substantially parallel slots 30 for receiving portions of the peripheral edges of regulating drive and rotary support wheels described hereinafter. The drive shaft 22 is connected by any suitable means to a source of power, such as a motor (not shown) and drives the driven shaft 26 through sprockets 32, 34 and chain 36.

First and second regulating drive wheels 38 and 40 are mounted on drive and driven shafts 22 and 26, respectively, for rotation therewith. A portion of the peripheral edge of each of these drive wheels extends through one of the slots 30 in the top surface 14 and contacts the bottom surface of a workpiece 42 supported thereon for rotating it.

A series ofv rotary support wheels 44, 46, 48 are also mounted in the housing 10 with portions of their peripheral edges extending through the slots 30 and contacting the workpiece. These support wheelsare mounted for free rotation on the driven and stationary shafts 26 and 28 so that they may rotate relative thereto and function to back up the workpiece and prevent it from being deflected and damaged during the abrading operation. If workpiece 42 is flat, the uppermost peripheral edges of wheels 38, 40, 44, 46, 48 will lie in a single horizontal plane.

As best shown in FIGURES 3 and 4, an abrading or grinding wheel 50 (shown in phantom lines in FIGURE 4) is suitably mounted for rotation above the flat disc like workpiece 42 for grinding its upper surface. The wheel may be a grinding wheel, for example, and the workpiece 42 may be a circular saw blade.

In order to insure that each of the regulating drive wheels 38 and 40 will tend to rotate the workpiece at the same speed and in a true rotary path, they must be driven so that their peripheral rates of speed will be directly proportional to their radial distances from the workpiece center of rotation. In the embodiment shown the regulating wheels 38 and 40 are driven at a 1:1 ratio by the shafts 22, 26 and the chain and sprocket arrangement 32, 34 and 36, and their circumferences correspond to the circumferences of the theoretical circles on the bottom surface of the workpiece, defined by the tangent points of contact between the peripheral edge of the drive wheels and the surface. In other words, the ratio of the circumference of the drive wheel 38 to the circumference of the theoretical circle on the bottom surface of the workpiece 42 defined by the tangent points of contact between the wheel 38 and the bottom surface of the workpiece must be substantially equal to the ratio of the cir' cumference of the wheel 40 to the circumference of the theoretical circle which it defines of the bottom surface of the work if there is a 1:1 drive ratio between wheels 36 and 40.

This same principle of regulated rotary motion may be accomplished by using two or more contact wheels turning at different, but controlled rotational speeds to match the surface or peripheral speeds of the tangent points of contact on the bottom surface of the workpiece.

As shown in FIGURES 14, the top surface 14 may be provided with a center pin 52 for positioning and defining the center of rotation of workpieces provided with center holes. This center pin is disposed along the center-of-rotation line 53 of the housing about which the workpiece rotates. As best shown in FIGURES 2 and 3, the center pin may have a cut-away portion defining a ledge 54 across a portion of which the stock removal wheel 50 may extend (see FIGURE 3) to insure that the entire surface of the workpiece 42 will be machined.

Alternatively, as shown in FIGURE 5, the center pin may be eliminated, and a cradle type rest 58 may be employed to position and guide rotational movement of the workpiece. This type of rest, in addition to being able to poistion workpieces not having center holes, may be used in conjunction with a suitable ejection device (not shown) for effecting automatic ejection of the workpiece upon completion of the grinding or abrading operation.

One or more work regulating pads 56, 56 may also be mounted on the top surface 14 for supporting the workpiece in a substantially flat turning plane during the grinding operation and prevent it from rocking. As best shown in FIGURE 2, two pads spaced approximately 120 degrees from one another and 120 degrees from the line of contact between the workpiece and wheels 38, 40, 44, 46, 48 may be employed. The pads may be made of any suitable material such as tungsten carbide, for example,

and will compensate for irregularities and distortion in the workpiece.

In operation, the regulating drive wheels 38 and 40 are rotated by the drive and driven shafts 38, 4t) and contact the battom surface of the workpiece to turn it in a rotary path. The stock removal grinding wheel 50 will also be rotated to turn the workpiece in the same direction as the regulating drive wheels (see FIGURES 4 and 5), but at a greater speed than the regulating wheels. Thus, due to the frictional drive contact of the regulating wheels with the workpiece, the regulating wheels will act as a brake, tending to slow and regulate the rotary motion of the workpiece. The rotary support wheels 44, 46, 48 will back up or stiffen the workpiece against deflection, and have a roller leveling effect on the workpiece. Minute blows of the abrading particles in the stock removing wheel constantly striking the workpiece in a rotary path and being backed up by the regulating and rotary support wheels have a hammer and anvil effect on the workpiece thus correcting distortion and making the finished workpiece fiat and parallel. The pads 56, 56 will compensate for irregularities on the botom surface of the work. After one face of the workpiece has been abraded, it is turned over and the other face is abraded.

The regulating drive unit of the present invention may be used in place of the conventional regulating wheel and workrest on centerless grinding machines to convert them for surface type work. The unit may also be employed wherever a rotary drive or regulating motion or combination of the two is required to hold and control a workpiece for flat or contour surface finishing. For example, the unit may be used in machines for flat and hollow, grinding of circular saw blades and knives; it may also be used efliciently for other abrading operations, such as brushing, buffing and polishing, on such items as hearing races, clutch discs, milling cutters, valve faces, lenses, cam plates, brake discs, etc.

' With the unit of this invention the workpiece is turned in a true rotary path and tends to remain in a true rotary path due to the different peripheral speeds of the regulating wheels being directly proportional to their distances from the center of workpiece rotation.

While the invention has been particularly shown and described with reference to preferred embodiments therethe foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A regulating drive unit for rotating a substantially flat surfaced workpiece during an abrading operation, comprising:

a housing having center-of-rotation line, and including a top surface having means defining a plurality of substantially parallel slots therein;

a drive shaft rotatably mounted in said housing; said drive shaft beingdisposed substantially parallel to, and spaced below said top surface;

a first regulating drive wheel mounted on said drive shaft for rotation therewith, and having a portion of its peripheral edge extending through one of said slots in said topsurface;

a driven shaft rotatably mounted in said housing; said driven shaftbeing' disposed substantially parallel to and between said drive shaft and said top surface; and

a second regulating drive wheel mounted on said driven shaft for rotation therewith, and having a portion of its peripheral edge extending through one of said slots in said top surface;

said first and second regulating drive wheels being spaced from each other and from the center-of-rotation line of said housing; and

positive drive connection means for driving said first and second regulating drive wheels so that their peripheral rates of speed are directly proportional to the distance they lie from the center-of-rotation line of the housing.

2. A regulating drive unit according to claim 1, and

further including a plurality of rotary support wheels mounted in said housing with portions of their peripheral edges extending through some of said slots in said top" surface for supporting a workpiece dispoesd adjacent said top surface.

3. A regulating drive unit according to claim 2, and

further including a plurality of regulating pads disposed on said top surface for contacting the bottom surface of the workpiece and compensating for irregularities thereon.

References Cited 3/1930 Great Britain.

HAROLD D. WHITEHEAD, Primary Examiner. 

1. A REGULATING DRIVE UNIT FOR ROTATING A SUBSTANTIALLY FLAT SURFACED WORKPIECE DURING AN ABRADING OPERATION, COMPRISING: A HOUSING HAVING CENTER-OF-ROTATION LINE, AND INCLUDING A TOP SURFACE HAVING MEANS DEFINING A PLURALITY OF SUBSTANTIALLY PARALLEL SLOTS THEREON; A DRIVE SHAFT ROTATABLY MOUNTED ON SAID HOUSING; SAID DRIVE SHAFT ROTATABLY MOUNTED IN SAID HOUSING; SAID AND SPACED BELOW SAID TOP SURFACE; A FIRST REGULATING DRIVE WHEEL MOUNTED ON SAID DRIVE SHAFT FOR ROTATION THEREWITH, AND HAVING A PORTION OF ITS PERIPHERAL EDGE EXTENDING THROUGH ONE OF SAID SLOTS IN SAID TOP SURFACE; A DRIVEN SHAFT ROTATABLY MOUNTED IN SAID HOUSING; SAID DRIVE SHAFT BEING DISPOSED SUBSTANTIALLY PARALLEL TO AND BETWEEN SAID DRIVE SHAFT AND SAID TOP SURFACE; AND A SECOND REGULATING DRIVE WHEEL MOUNTED ON SAID DRIVEN SHAFT FOR ROTATION THEREWITH, AND HAVING A PORTION OF ITS PERIPHERAL EDGE EXTENDING THROUGH OND OF SAID SLOTS IN SAID TOP SURFACE; SAID FIRST AND SECOND REGULATING DRIVE WHEELS BEING SPACED FROM EACH OTHER AND FROM THE CENTER-OF-ROTATION LINE OF SAID HOUSING; AND POSITIVE DRIVE CONNECTION MEANS FOR DRIVING SAID FIRST AND SECOND REGULATING DRIVE WHEELS SO THAT THEIR PERIPHERAL RATES OF SPEED ARE DIRECTLY PROPORTIONAL TO THE DISTANCE THEY LIE FROM THE CENTER-OF-ROTATION LINE OF THE HOUSING. 